Noun
an antenna that transmits or receives signals only in a narrow angle
Source: WordNetAt wavelengths of 30 meters to 3 meters (10 MHz - 100 MHz), they are generally either directional antenna arrays similar to "TV antennas" or large stationary reflectors with moveable focal points. Source: Internet
In a directional antenna in which the objective is to emit the radio waves in one direction, the lobe in that direction is designed to be bigger (have higher field strength) than the others; this is the main lobe. Source: Internet
In every direction, the power gain of an isotropic antenna is equal to the efficiency, and hence is always at most 1, though it can and ideally should exceed 1 for a directional antenna. Source: Internet
In the figure to the left, assume that each display is connected to a spectrum analyzer connected to a directional antenna aimed in the indicated direction. Source: Internet
The term gain has a different meaning in antenna design; antenna gain is the ratio of radiation intensity from a directional antenna to (mean radiation intensity from a lossless antenna). Source: Internet